1. Field of the Invention
The present invention relates to a liquid jet recording head used for a device for recording by ejecting and projecting a recording liquid, so-called ink, and more particularly, to a liquid jet recording head used for a liquid jet recording device capable of stable recording continuously ranging from a super high speed to a low speed.
2. Description of the Prior Art
Non-impact recording processes have recently drawn attention since the noise accompanying recording operation is negligibly small.
Among them, an ink jet recording process (liquid jet recording processes) which can effect a high speed recording and can record on plain paper without fixation are very powerful processes. Heretofore, a wide variety of systems and apparatuses therefore have been proposed. Some of them have been practically operated while others are now under development.
Such ink jet recording device (liquid jet recording device) ejects a recording liquid, so-called ink, from an ejecting orifice provided at a recording head and projects the droplets toward a record member and the droplets impinge on the record member to effect recording.
Such recording device may be constituted in various ways depending upon the recording mode applied thereto. Anyway, the principle of the method for ejecting and projecting the recording liquid is simple and can be used for high speed recording. One of the effective recording devices utilizing such method is a device in which a recording liquid is ejected and projected by applying an electric signal to an electromechanical transducer provided on the recording head resulting in mechanical deformation thereof. This is disclosed in detail, for example, in U.S. Pat. No. 3,683,212.
The principle of projecting liquid droplets by the recording device disclosed in U.S. Pat. No. 3,683,212 is that electric impulses (electric signals) are applied to a cylindrical electromechanical transducer mounted on the recording head through a lead electrode to cause a change of the inner diameter of the transducer in a pulsating manner resulting in a change in the volume of the pressure generating portion. The ejected droplets impinge on a record member. A volume of the recording liquid corresponding to the volume of the recording liquid thus ejected is supplied through an inflow conduit communicating with the pressure generating portion when the volume of the pressure generating portion returns to the original one.
Such recording head can continuously and stably effect recording only when the maximum frequency of generating droplet is at most several tens of KHz and therefore, the high speed recording by using one piece of such recording head is limited to a great extent. A solution to this problem is that a plurality of such recording heads are arranged to improve the maximum recording frequency resulting in a substantially high speed recording. In such case, it is necessary for increasing the resolution that positioning of each recording head in the array is accurate to a great extent. For example, usual images of good quality require a resolution as high as 10 pel/mm. In this case, the positioning of each recording head should be effected at an accuracy of 1/10 mm or at a higher accuracy. These are remarkable disadvantageous for productivity and mass production and disturb commercial production.
The above mentioned drawbacks increase in a geometrical progression as the number of the arranged recording heads increase, and as the result, yield of production of the recording head decreases to a great extent. The more the number of the recording heads to which a lead electrode is to be connected, the more complicated the wiring of lead electrodes for input signals. Further, the electrical insulation among the lead electrodes should be taken into consideration.
The electromechanical transducer of the above mentioned recording head is fixed, with adhesives, to the outer peripheral surface of a cylinder member made of glass or the like having an ejecting orifice at the tip. At present the accuracy of shape and dimension of electromechanical transducers is at most about .+-.10 .mu.m, and therefore, when many recording heads are arranged to form a multiorifice system, it is fundamentally difficult to improve the accuracy of arrangement. As the result, recording devices capable of producing recorded images of high resolution according to the above system can not be easily manufactured and the mass production is difficult and the productivity is low.